MiR390 is a conserved miRNA family and that has been confirmed to play pleiotropic roles in regulating the growth and development of plant species. Broccoli (B. oleracea L var. italica) is an important varietas of B. oleracea with abundant nutrients and cultivated worldwide. However, the mechanism underlying the miR390-mediated regulation of organ development in broccoli remains unknown. In the present study, bol-miR390a, a member of miR390 family, was identified in broccoli. Bol-miR390a displayed significantly differential expression patterns with the development of various broccoli organs. Ectopic overexpression of bol-miR390a accelerated the lateral organ development of transgenic lines in Arabidopsis. The lateral branches and roots of overexpressed bol-miR390a transgenic Arabidopsis were greater than those of the vector controls; thus, the biomass of 35S::bol-miR390a plants significantly increased relative to those of the vector controls. Moreover, the present results demonstrated that the expression levels of TRANS-ACTING SIRNA3 (TAS3)-derived siRNAs (tasiRNAs) displayed positive correlation with those of the bol-miR390a, whereas TAS3 and several auxin response factors (ARFs) including ARF2, ARF3, and ARF4, which were the potential targets of tasiRNAs, showed decreased expression trends in the overexpressed bol-miR390a transgenic plants compared with those in the vector controls. These results suggested that the bol-miR390a/TAS3/ARFs module might play important roles in the lateral organ development of broccoli. In summary, these findings confirmed that bol-miR390a is a crucial regulator in the lateral development of broccoli and suggested the potential application of bol-miR390a in breeding high-biomass crops and economic plants.

中文翻译：

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来自西兰花（B. oleracea L var. italica）的 bol-miR390a 的异位过表达增加了拟南芥的侧枝

MiR390 是一个保守的 miRNA 家族，已被证实在调节植物物种的生长和发育中发挥多效作用。西兰花 (B. oleracea L var. italica) 是 B. oleracea 的一个重要品种，营养丰富，在世界范围内均有栽培。然而，miR390 介导的西兰花器官发育调控的机制尚不清楚。在本研究中，bol-miR390a 是 miR390 家族的成员，在西兰花中被鉴定出来。随着各种西兰花器官的发育，Bol-miR390a 显示出显着差异的表达模式。bol-miR390a 的异位过表达加速了拟南芥转基因品系的侧器官发育。过表达bol-miR390a转基因拟南芥的侧枝和根均大于载体对照；因此，与载体对照相比，35S::bol-miR390a 植物的生物量显着增加。此外，目前的结果表明 TRANS-ACTING SIRNA3 (TAS3) 衍生的 siRNAs (tasiRNAs) 的表达水平与 bol-miR390a 的表达水平呈正相关，而 TAS3 和几种生长素反应因子 (ARFs) 包括 ARF2、ARF3、作为 tasiRNA 的潜在靶标的 ARF4 和 ARF4 在过表达的 bol-miR390a 转基因植物中显示出与载体对照相比降低的表达趋势。这些结果表明 bol-miR390a/TAS3/ARFs 模块可能在西兰花侧器官发育中发挥重要作用。总之，